Tristan and Isolde are star-crossed lovers from Arthurian myth, whose story has since been retold in many variations throughout literature, music and film. The story tells of the adulterous love between the Cornish knight Tristan and the Irish princess Isolde.

Tristan and Isolde is also referred to later on page 863 (see bookmark) in a scene with reformed convict and drug addict Don Gately.

'Droogies' means 'friends' in the language of Nadsat, created by Anthony Burgess for his novel A Clockwork Orange.

Nadsat is a form of Russian-influenced English, and is used by the anti-hero protagonist Alex. Burgess came up with the language in order to give the novel a unique and timeless voice. A full glossary can be found here.

Tiziano 'Titian' Vicelli was a 16th century Italian painter and an influential figure in the High Renaissance movement. His most notable works included The Assumption of the Virgin, the Pesaro Altarpiece and Venus of Urbino.

Gordon Brown - Credit: IMF

David Cameron - Credit: World Economic Forum

In February 2009, he was the subject of an argument between British Prime Minister Gordon Brown and the Leader of the Opposition David Cameron. Brown had previously referred to Titian as having died aged 90, which Cameron later ridiculed in order to highlight the PM's general factual inaccuracy. However, the precise date of Titian's birth remains uncertain. A worker from Conservative Party HQ was disciplined after they edited the artist's Wikipedia page in order to substantiate Cameron's claims.